Acid-resistant alloy



Patented Apr. 8, 1930 UNITED STATES PATENT OFFICE GLAYTON E. PLUMMER, OF LA GRANGE, ILLINOIS, ASSIGNOR TO ELECTRO METAL- Ii'U'IEtG-ICLAIILI COMPANY, A CORPORATION OF WEST VIRGINIA ACID-RESISTANT ALLOY No Drawing.

Per cent Nickel 85 Silicon 10 Aluminum 1.5-2.0 Copper 2.5-3.0

A small proportion of iron may also be present, it should, however, be kept below 0.5% since higher percentages result in a loss of strength and a decrease in the acid resist ance, especially if the iron content is greater than 1%. The aluminum desirably should not exceed 2% since higher proportions of aluminum cause the strength to be reduced. The copper content may be increased to as much as without decreasing the acid resistance but above 3% a greater hardness and lower strength are produced. The silicon content should be held within fairly close limits to that indicated, preferably plus or minus 1%. With more than 11% of silicon, the hardness and brittleness of the alloy increase and below 9%, the resistance to acid is not so good.

In the manufacture of the alloy, it is con venient to melt the silicon and nickel together and add the small amounts of copper and aluminum to the melt just before pouring, since they go into solution quickly and easily. While no dificulty is to be anticipat-ed from segregation, the molten alloy may be stirred with a graphite rod before pouriihe molten metal is fluid and fills the molds readily without undue shrinkage.

Standard arbitration bars of the above alloy show a strength, when broken in transverse between supports 12 apart, as high as 5200 pounds with a deflection 0f'0.083 and the Application filed November a, 1928. SeriaI No. 317,117.

average breaking strength of a considerable number was found to be well above 4500 pounds with a defiectionof 0.070 or more. Thus castings made from such bars show high strength.

The material is both tough and hard. It is not sufficiently soft to be readil adapted to machining and any finishing o the castings is preferably done by grinding or similar operations.

The resistance of the alloy' of my invention to acids is considerably higher than the well-known silicon-irons, and other commercial acid resistant alloys. B y the composition of my invention I have thus produced a new and useful alloy having high strength and toughness, and high resistance to corrosion agents.

lVhile I have shown but a single embodiment of the alloy of my inventionit is adapted to modification therefrom without departure from the spirit thereof and it is desired therefore that only such limitations shall be imposed upon the appended claims as are required by the prior art or indicated therein.

I claim as my invention:

1. An improved acid-resistant alloy consisting of nickel, silicon, copper and aluminum within the following proportional limits:

Silicon 9.0 to 11.0% Copper 2.5 to 25.0% Aluminum 1.5 to 2.0% Nickel Balance CLAYTON E. PLUMMER. 

